The release script asks the user if it should create a branch for the release and the next version that should be use. This question is asked after pulling the repo and checking first if the branch doesn't yet exist and we need to keep that check.
However, once the question has been answered, we should be able to reuse it for all other repo: right now when releasing we have to answer it first for xwiki-commons, then for rendering and then for platform. It forces to keep an eye on the logs as it's blocking the release until there's an answer.